Novel photographic processes



. positive dye image.

United States Patent 3,249,432 NOVEL PHOTOGRAPHIC PROCESSES Howard C.Haas, Arlington, Mass, assignor to Polaroid Corporation, Cambridge,Mass., a corporation of Delaware No Drawing. Filed Aug. 22, 1960, Ser.No. 50,846 Claims. (Cl. 96-29) The present invention relates tophotography and more particularly to processes for protecting colordiifusionand the scope of the application of which will be indicated inthe claims. I

For a fuller understanding of the nature and objects of the invention,reference should be had to the following detailed description.

The copending US. application of Howard G. Rogers, Serial No. 748,421,filed July 14, 1958 (now US. Patent No. 2,983,606, issued May 9, 1961),discloses and claims processes wherein dye developers (i.e., compoundswhich contain, in the same molecule, a silver halide developing functionand the chromophoric system of a dye) are used to form color transferimages. In such processes, a photosensitive element is exposed to createtherein a latent image. The latent image is developed in the presence ofa dye developer and an imagewise distribution of unreacted dyedeveloper, from which the positive image may be created, is formed. Atleast a portion of said unreacted dye developer is transferred to asuperposed image-receiving layer to create thereon a positive image. Theprocesses are preferably carried out by disposing the dye developer inthe photosensitive element prior to exposure and causing it to besolubilized therefrom by an alkaline processing liquid which is appliedbetween the superposed photosensitive element and image-receivingelement. As the process proceeds, the exposed silver halide is reducedto metallic silver and the portions of the dye developer which areoxidized, as a result of the silver development,

' are substantially immobilized in exposed areas.

At least a portion of the unreacted dye developer is imbibed on thesuperposed image-receiving layer to create thereon the The positiveimage is preferably viewed by stripping the photosensitive element fromthe image-receiving layer.

The color fastness of the colored photographic images, produced in suchprocesses, upon prolonged exposure to sunlight often leaves something tobe desired. It has been discovered that the color stability of suchimages in sunlight can be appreciably enhanced by using a salt andespecially a halogen salt as a stabilizer. Particularly good resultshave been obtained from halides selected from the group consisting ofthe chlorides, iodides and 3,249,432 Patented May 3, 1966 tioncomprising the particular salt which is to be employed. The solution maybe conveniently applied to the colored image by immersion, swabbin-g,coating, spraying, flowing, etc. In an especially useful embodiment, thesolution may also comprise a film-forming polymer, such as gelatin,which will serve as a protective surface coating for the image. Toinsure that the stabilizer will be intimately associated with the dyedevelopers in the imagereceiving layer, it is preferable to apply suchstabilizers from a solvent which will permeate the image-receiving ayer.I

Another mode of carrying out the processes of this invention is toincorporate the salt into the image-receiving element prior to their usein the dye developer transfer processes. Such image-receiving elementsgenerally comprise a sheet of dye-receptive material and, in preferredembodiments, comprise a film support bearing a coating of a dyeablematerial. The salt stabilizer may be incorporated by adding it to thecoating solution of dyeable material and applying it therewith to thefilm support, or it may be applied, as above, by permeation. As examplesof dyeable materials which have been found useful in preparingimage-receiving elements, mention may be made ofp-trimethylammonium-p-toluene-sulfonate benzal of polyvinyl alcohol,N-methoxymethyl polyhex-amethylene adipamide, polyvinyl alcohol,crosslinked polyvinyl alcohol (i.e., polyvinyl alcohol which has beenreacted with a crosslinking agent such as glyoxal or dimethylolurea),mixtures of polyvinyl alcohol and poly-N-vinyl pyrrolidone, andcopolymers of vinyl alcohol and N-vinyl pyrrolidone.

Still another mode of carrying out the processes of this invention is toincorporate the salt stabilizers into the image-receiving element bothbefore its use in transfer processes and again after the positive imagehas been formed thereon. Such a mode is especially effective in assuringan intimate association of the stabilizers with the dye developers whichthey are intended to protect.

In an especially useful embodiment of this invention, the saltstabilizers are used in combination with an ultraviolet light absorber.The use of the stabilizers herein disclosed in combination with suchabsorbers substantially enhances the ability of the latter in protectingthe transfer images from the deleterious effects of sunlight. Theabsorbers may be applied from the same coating solution containing thesalt stabilizers or they may be applied separately. When the absorbersare applied separately, methodssuch for example as those disclosed inthe copending application of Howard G. Rogers, Serial No. 786,- 766,filed January 14, 1959, now abandoned, may be employed. In one suchmethod disclosed therein, the absorbers are incorporated in a permeable,substantially nondyeable layer over the image-receiving layer prior toprocessing, and during processing the dye developers are transferredthrough such layers. In another method the absorbers are transferredfrom the photosensitive element along with the un-reacted dyedevelopers.

The amount of stabilizer used will vary with many factors such, forexample, as the original color fastness of the dye developers, theamount of sunlight the colored image will be exposed to during its lifeexpectancy, etc. The amount of stabilizer employed to provide protectionmay be referred to as an effective amount, i.e., an amount suificient togive the desired protection, and it will be understood that such anamount will vary with factors, such as mentioned above, and can bereadily determined through color-fading tests which will hereinafter bedescribed. In most cases, when the coating solutions comprise afilmforming material, 5.0 to 20% of the halide stabilizer, based on theweight of the polymer, will be effective in enhancing the colorstability of the images. When the coating solution does not contain afilm-forming material, use of 5 to 10% solutions of the halidestabilizers gives especially effective results.

' The dye developers which are used in the processes, as noted above,are compounds which contain in the same molecule both the chromophoricsystem of a dye and also a silver halide developing function. By asilver halide developing function is meant a grouping adapted to developexposed silver halide. A preferred silver halide developing function insuch dye developers is a hydroquinonyl group. Other suitable developingfunctions include o-dihydroxyphenyl and oand p-amino-substitutedhydroxyphenyl groups. In general, the developing function is usuallysupplied by the presence in the molecule of a benzenoid developingradical. of representative dye developers are given in thepreviously-mentioned application of Howard G. Rogers. Additional usefuldye developers are described in the following copending US.applications:

Application Serial No. 612,045, filed September 25, 1956, in the namesof Elkan R. Blout, Milton Green and Howard G. Rogers (now abandoned andreplaced by a continuation-in-pa'rt thereof, application Serial No.144,816, filed October 18, 1961) now US. Patent No. 3,134,672;

Application Serial No. 612,052, filed September 25, 1956, in the namesof Milton Green and Howard G. Rogers (now abandoned and replaced by acontinuationin-part thereof, application Serial -No. 165,930, filedJanuary 12, 1962) now US. Patent No. 3,135,604;

Application Serial No. 612,053, filed September 25,

1956, in the name of Myron S. Simon (now abandoned and replaced by acontinuation-in-part thereof, application Serial No. 196,523, filed May21, 1962) now US. Patent No. 3,183,089;

Application Serial No. 612,054, filed September 25, 1956, in the namesof Helen P. Husek and Myron S. Simon (now abandoned and replaced by acontinuation-inpart thereof, application Serial No. 197,283, filed May24, 1962);

Application Serial No. 612,055, filed September 25, 1956, in the name ofHelen P. Husek (now abandoned and replaced by a continuation-in-partthereof, application Serial No. 192,3 55, filed May 4, 1962);

Application Serial No. 755,804, filed August 18, 1958, in the names ofElkan R. Blout, Saul G. Cohen, Milton Green and Myron S. Simon (nowabandoned);

Application Serial No. 824,785, filed July 3, 1959, in the names ofElkan R. Blout, Marilyn R. Cohler, Milton Green, Myron S. Simon andRobert B. Woodward (now abandoned and replaced by a continuation-in-partthereof, application Serial No. 233,461, filed October 26, 1962) now US.Patent No. 3,135,606;

Application Serial No. 849,727, filed October 30, 1959, in the names ofElkan R. Blout and Myron S. Simon (now abandoned);

Application Serial Nos. 1,442 and 1,443 filed January 11, 1960, in thenames of Elkan R. Blout, Saul G. Cohen, Milton Green, Howard G. Rogers,Myron S. Simon and Robert B. Woodward.

The following nonlirniting examples illustrate the effec tiveness of theprocesses of the present invention:

Example 1 Film supports bearing N-methoxymethyl polyhexamethyleneadipamide dyeable layers were dyed from 0.086 molar2-[p-(2',5'-dihydroxyphenethyl-phenylazo]- 4-propoxy -1-naphthol, (amagenta dye developer) dye baths containing 2% alkali and 1%, 5%, and20% potassium iodide. The dyed sheets were placed 20.5 inches from abattery of six 275 watt General Electric sunlamps spaced 7.5 inchesapart. Measurements of Examples 4 the density and hmax. of the dyedsheets after the elapse of various periods of time, showed thefollowing:

(A) 0% KI:

Hours Exposed Density km.

0 hours 0. 53 530 40 hours O. 04 530 (B) 1% KI:

Hours Exposed Density hmx.

0 hours 0. 46 530 40 hours 0. 27 530 Hours Exposed Density )wnnx.

0 hour 0. 57 530 40 hours 0. 233 530 (D) 10% KI:

Hours Exposed Density )unnx.

0 hours 0.44 530 40 hours 0. 23 530 (E) 20% KI:

Hours Exposed Density )Hnnt.

0 hours 0. 51 530 40 hours 0. 325 530 Example 2 A film support bearingan N-methoxymethyl polyhexamethylene adipamide dyeable layer was soakedin saturated potassium iodide and then dyed in a 0.086 molar 2 [p- 2',5'-dihydroxyphenethyl) -phenylazo -4-propoxyl-naphthol dye bathcontaining 2% alkali for 15 seconds. Measurements of the density and kof the sheet after various periods of exposure to the battery ofsunlamps showed the following:

Hours Exposed Density )unnx.

0 hours 0.64 530 40 ho r 0. 335 530 Example 3 Hours Exposed Density Am.

0 hours 0. 54 5a 40 hours 0.43 538 86 hours 0. 365 530 146 hours 0. 31530 Example 4 A film structure prepared and dyed in a manner similar tothat employed in Example 3 was coated with a 4:1 ethyl alcohol-watersolution comprising 20% N-methoxymethyl polyhexamethylene adipamideand2% potassium Film structure (c)-Agent At-3l6 and 2.0% KI:

iodide. Upon exposure to the battery of sunlamps mentioned above, thefollowing results were obtained: Hours Exposed Density r Hours ExposedDensity )nnnx, 5 0 hours 0.76 530 72 hours 0'. 75 530 ours 0. 1 48 hours0.54 530 Film structure (d) TBS and 2. 72 hours 0. 49 530 10 HoursExposed Density Am.

Example 5 0 hours 91 3 72h .84

A filmstructure was dyed and coated 1n a manner srmrours a lar to thatemployed in Example 4 except that 2% p0- Although the above examplesutilize a single dye tassiurn bromide was used in place of the potassiumiodide in the adipamide coating solution. Upon exposure to the batteryof sunlamps, the following changes in density were observed:

Hours Exposed Density hm.

0 hours 0.61 530 24 hours 0. 46 530 48 hours 0.22 530 Example 6 A seriesof dyed film structures similar to those employed in Example 4 werecoated with the following 4:1 ethyl alcohol-water coating solutionscomprising:

Film structure (a): Percent N-methoxymethyl polyhexamethylene adipamideUvinul 490 (trade name of Antara Chemicals, a division of GeneralAniline & Film Corp., New York, N.Y., for a substituted benzophenoneultraviolet light absorber) 2.0 Film structure (b):

N-methoxymethyl polyhexamethylene adipamide 20 Uvinul 490 2.0 Potassiumiodide 2.0

- Film structure (c):

N-methoxymethyl polyhexamethylene adipamide 20 Potassium iodide 2.0

Agent At3 16 (trade name of Antara Chemicals for a substitutedbenzophenone ultraviolet light absorber) Saturated-solution Filmstructure (d):

N-methoxymethyl polyhexamethylene adipamide 20 Potassium iodide 2.0T.B.S. (trade name of Dow Chemical Co., Midland, Michigan for a4-tert.-butylphenyl salicylate ultraviolet light absorber) Saturatedsolution Upon exposure to the battery of sunlamps the following resultswere obtained:

. developer, it is to be understood that this was for purposes ofillustration only and that the processes of this invention are equallyeffective in stabilizing multicolored images produced by processeswherein a plurality of dye developers are used to form the transferimage. As examples of such multicolor processes, mention may be made ofthe processes disclosed and claimed in the pre viously-mentionedcopending application of Howard G. Rogers, and in the copending U.S.application of Edwin H. Land and Howard G. Rogers, Serial No. 565,135,filed February 13, 1956.

Image-receiving elements having image-receiving layers of thep-trimethyiammonium-p-toluene-sulfonate benzal of polyvinyl alcohol andbearing multicolor stepwedge-images, produced through processes such asdisclosed in the above-mentioned copending applications of 'Edwin H.Land and Howard G. Roger's with the use of the above-mentioned 2- [p-2,5 -dihydroxyphenethyl) -phenylazo]-4-propoxy 1 naphthol (magenta dyedeveloper) along with 1,4-bis-[B (2,5dihydroxyphenyl)-isopropylamino]-5,8-dihydroxyanthraquinone (a cyan dyedeveloper) and 1 phenyl 3 N-n-hexyl-carbarnyll-[p- (2',5'dihydroxyphenethyl) phenylazo] -5 pyrazolone (a yellow dye developer)were coated with the following coating solutions: (1) a coatingcomprising 1% lithium bromide and 10% gelatin, (2) a coating solutioncomprising 1% cesium bromide and 10% gelatin and (3) a coating solutioncomprising 1% lithium chloride and 10% gelatin. The image-receivingelements along with a control were exposed to an Atlas Fadeometer,equipped with a Xenon arc. After 96 hours of exposure it was observedthat the light stabilities of the images treated with the stabilizers ofthis invention were substantially better than that of the untreatedcontrol.

Other halides which were tested on multicolor stepwedge-images such asmentioned above and were found effective in improving the lightstability are lithium bromide, calcium chloride, cadmium bromide,cadmium chloride, magnesium bromide, calcium bromide, magnesiumchloride, sodium bromide, cesium chloride, and sodium chloride.

Other non-halide salts which have been found effective as stabilizersbut which appear to be not as effective as the halide salts wereammonium sulfate and aluminum sulfate.

Since certain changes may be made in the above processes withoutdeparting from the scope of the invention herein involved, it isintended that all matter contained in the above description shall beinterpreted as illustrative and not in a limiting sense.

What is claimed is:

1. In a process of forming a photographic image in color wherein anexposed silver halide emulsion is developed in the presence of a dyedeveloper to provide a predetermined distribution of unoxidized dyedeveloper, and at least part of said distribution of unoxidized dyedeveloper is transferred from said emulsion to a superposedima'ge-receiving layer to provide a positive dye image of thephotographed image, the improvement which comprises increasing thestability of said positive 6. A process as defined in claim 2 whereinsaid halide.

salt is a chloride.

7. A process as defined in claim 1 wherein said halide salt is used incombination with an organic ultraviolet light absorber.

8. In a process of forming a photographic image in color,'the stepswhich comprise developing an exposed silver halide emulsion with anaqueous alkaline solution containing a dye developer. to provide in saidemulsiona predetermined distribution of unoxidized dye developer, andtransferring at least part of said distribution of said unoxidized dyedeveloper from said emulsion to an image-receiving layer in superposedrelationship with said emulsion to impart to said image-receiving layera reversed positive dye image of the developed image, saidimage-receiving layer having incorporated therein a halide salt of analkali metal, whereby the stability of said positive dye image isincreased.

9. A process as defined in claim 8 wherein said halide salt is selectedfrom the group consisting of iodides, bromides and chlorides.

10. A process as defined in claim halide salt is an iodide.

11. A process as defined in claim halide salt is a bromide.

12.;A process as-defined in claim halide salt is a chloride.

13. A process as defined in claim 8 wherein halide salt is used incombination with an organic ultraviolet light absorber.

14. A process as defined in claim 8 including the steps, subsequent tothe transfer of the unoxidized dye developer to said image-receivinglayer, of separating said image-receiving layer from said emulsion andtreating 9 wherein 9 wherein said 9 wherein said said said i 8 saidimage-receiving layer with a solution comprising said halide salt.

15. In a process of forming a photographic image in color, the stepswhich comprise developing an exposed silver halide emulsion with anaqueous alkaline solution containing a dye developer to provide in saidemulsiona predetermined distribution of unoxidized dye developer, andtransferring at least part of said distribution of said unoxidized dyedeveloper fron said emulsion to an image-receiving layer in superposedrelationship with.

said emulsion to impart to said image-receiving layer a reversedpositive dye image of the developed image, said image-receiving layerhaving incorporated therein potassium iodide- References Cited by theExaminer UNITED STATES PATENTS 2,747,996 5/1956 Edgerton et al. 96112,892,383 6/1959 Walworth et al. 101-l49.1 X 2,913,338 11/1959 Bates etal. 96290 2,931,296 4/1960 Ryan et al. 1()1 149.1 2,997,390 8/1961 Land9629 3,061,453 10/ 1962 Rogers 9629 3,065,074 11/1962 Rogers 96293,081,167 3/1963 Goulston et al. 9629 FOREIGN PATENTS 220,279 12/1959Australia;

1,083,651 6/1960 1 Germany.

OTHER REFERENCES Evans et a1. Principles of Color Photography, JohnWiley & Sons, New York, 1953, pages 26869.

Journal of the Chemical Society, Transactions, 109, pp. 1277-1286(1916).

Plyler et al., Journal of the Optical Society of America, 42, June 1952p. 433.

Sawyer, R. A., Experimental Spectroscopy, Prentice- Hall, New York(1946), p; 69.

NORMAN G. TORCHIN, Primary Examiner.

PHILIP E. 'MANGAN, Examiner.

B. E. EDELSTEIN, G. H. BJORGE, J. T. BROWN,

Assistant Examiners.

1. IN A PROCESS OF FORMING A PHOTOGRAPHIC IMAGE IN COLOR WHEREIN ANEXPOSED SILVER HALIDE EMULSION IS DEVELOPED IN THE PRESENCE OF A DYEDEVELOPER TO PROVIDE A PREDETERMINED DISTRIBUTION OF UNOXIDIZED DYEDEVELOPER, AND AT LEAST PART OF SAID DISTRIBUTION OF UNOXIDIZED DYEDEVELOPER IS TRANSFERRED FROM SAID EMULSION TO A SUPERPOSEDIMAGE-RECEIVING LAYER TO PROVIDE A POSITIVE DYE IMAGE OF THEPHOTOGRAPHED IMAGE, THE IMPROVEMENT WHICH COMPRISES INCREASING THESTABILITY OF SAID POSITIVE DYE IMAGE BY TREATING SAID POSITIVE DYEIMAGE, SUBSEQUENT TO ITS FORMATION, WITH A HALIDE SALT OF AN ALKALIMETAL.